* {
    margin: 0;
    padding: 0;
}

body {
    height: 100vh;
    /* 设置伸缩盒子模型 */
    display: flex;
    /* 设置body子类居中 */
    justify-content: center;
    align-items: center;
    background-color: #2c3e50;
}

.container {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    width: 300px;
    height: 450px;
    border-radius: 20px;
    background-color: #34495e;
    box-shadow: 15px 15px 10px rgba(33, 45, 58, .3);
    overflow: hidden;
    position: relative;
}

.container form {
    width: 400px;
    height: 200px;
    display: flex;
    justify-content: space-around;
    flex-direction: column;
    align-items: center;
    z-index: 1;
}

.container form .tbx {
    width: 200px;
    height: 40px;
    outline: none;
    border: none;
    border-bottom: 1px solid #fff;
    background: none;
    color: #fff;
}

.container form .tbx::placeholder {
    color: #fff;
    font-size: 15px;
}

.container form .btn {
    width: 200px;
    height: 40px;
    outline: none;
    border: 1px solid #fff;
    border-radius: 20px;
    letter-spacing: 5px;
    color: #fff;
    background: none;
}

.container h1 {
    z-index: 1;
    color: #ecf0f1;
    letter-spacing: 5px;
    padding-left: 5px;
    font-size: 40px;
    font-weight: 100;
    text-shadow: 5px 5px 5px rgba(33, 45, 58, .3);
}